Myopia is a very common visual problem affecting millions of individuals in this country. It rarely requires therapy other than spectacles or contact lenses, and these have been successful in the vast majority of cases without complications for many years. The surgical correction of myopia has recently received widespread usage in Russia by radial non-penetrating corneal incisions to reduce corneal curvature. Radial keratotomy (Fyodorov-Sato) has been performed in hundreds of Russian patients. This surgical procedure will soon be introduced into American ophthalmology. Any surgical procedure for the correction of myopia has the potential for complication involving visual loss and should be studied in animals and human clinical trials until safety and efficacy can be determined. The purpose of this proposal is to study the short and long term clinical and pathological effects of radial keratotomy in primate eyes. The mechanism of action of this procedure, and more importantly, histopathologic studies and trials in humans or animals have not been reported to date. The short and long term effects, both clinical and pathologic, will be studied for sub-clinical damage to the posterior layers of the cornea including the endothelium/ Descement's membrane complex, angle structures, etc. If precise mechanisms can be determined, it is possible that changes and simplifications of the technique may be possible. Utilization of a primate model for radial keratotomy would, hopefully, permit determination and clarification of these mechanisms with especially close attention to histopathologic changes involved in this procedure. In addition, we will isolate surgical variables to determine which are the most important. What is the optimal optical zone? What depth of incision is effective and safe? Is the length of incision important, and is incision beyond the limbus necessary? How many incisions are required to be effective? Such questions need to be answered in animal studies before the procedure is used on humans in this country. The primate cornea is very similar to the human cornea and direct clinical relevance is expected from such studies.